Vertical recovery for an unmanned underwater vehicle

Abstract

A recovery system for an unmanned underwater vehicle (UUV) includes an elongate recovery container sized to contain the UUV, and a recovery cable coupled to the elongate recovery container, where the recovery cable is retractable into the elongate recovery container to capture and stow the UUV within the elongate recovery container. The system also includes the UUV, which includes a forward looking sonar system configured to locate the recovery cable and a capture clip coupled to a nose portion of the UUV, where the capture clip is configured to be releasably secured to the recovery cable. The UUV further includes at least one ballast tank capable of trimming the UUV to a vertical orientation.

What is claimed is: 
     
       1. A recovery system for an unmanned underwater vehicle (UUV), comprising:
 an elongate recovery container sized to contain the UUV; 
 a recovery cable coupled to the elongate recovery container, wherein the recovery cable is retractable into the elongate recovery container to capture and stow the UUV within the elongate recovery container; and 
 the UUV, comprising:
 a forward looking sonar system configured to locate the recovery cable; 
 a capture clip coupled to a nose portion of the UUV, wherein the capture clip is configured to be releasably secured to the recovery cable; and 
 at least one ballast tank capable of trimming the UUV to a vertical orientation. 
 
 
     
     
       2. The system of  claim 1 , wherein the elongate recovery container comprises a first end that is openable to pay out the recovery cable, and wherein the recovery cable is retractable into the elongate recovery container via the first end. 
     
     
       3. The system of  claim 1 , wherein the at least one ballast tank comprises a forward ballast tank fluidly coupled to an aft ballast tank. 
     
     
       4. The system of  claim 1  further comprising a stop positioned on the recovery cable, wherein the capture clip comprises:
 a loop releasably coupled to a side of the UUV, wherein the loop comprises a gap that is closed by a gate, and wherein the loop surrounds an opening that is larger than a diameter of the recovery cable and smaller than a diameter of the stop; and 
 a lead cable coupling the loop to the nose portion of the UUV. 
 
     
     
       5. The system of  claim 4 , wherein the gate comprises a spring, and wherein the gate is openable by a movement of the UUV against the recovery cable to apply a force to the gate from an outside of the loop, thereby compressing the spring. 
     
     
       6. They system of  claim 4 , wherein the capture clip further comprises a guide finger positioned adjacent to the loop, wherein the guide finger is extendable from the side of the UUV and shaped such that the recovery cable is biased toward the gap when in contact with a forward edge of the guide finger when the guide finger is extended. 
     
     
       7. The system of  claim 1 , wherein the elongate recovery container comprises a winch positioned within the elongate recovery container, and wherein the recovery cable is retractable into the elongate recovery container by winding the recovery cable onto the winch. 
     
     
       8. The system of  claim 7 , wherein the winch comprises a force sensor configured to detect a tensile force on the recovery cable. 
     
     
       9. The system of  claim 1 , wherein the UUV further comprises an acoustic communications array configured to transmit an indication to the elongate recovery container. 
     
     
       10. A method for recovery of an unmanned underwater vehicle (UUV), comprising:
 locating, via a forward looking sonar system of the UUV, a recovery cable that extends underwater in a vertical orientation, wherein the recovery cable is coupled to an elongate recovery container that is positioned underwater in a vertical orientation; 
 guiding the UUV toward the recovery cable; 
 releasably securing the UUV to the recovery cable via a capture clip coupled to a nose portion of the UUV; 
 adjusting at least one ballast tank to trim the UUV to a vertical orientation; and 
 causing the elongate recovery container to retract the recovery cable. 
 
     
     
       11. The method of  claim 10 , wherein the elongate recovery container comprises an upward-facing first end, and wherein the method further comprises:
 opening the upward-facing first end of the elongate recovery container; 
 paying out the recovery cable, wherein the recovery cable comprises a buoyant portion configured to draw the recovery cable upward out of the elongate recovery container; and 
 wherein causing the elongate recovery container to retract the recovery cable comprises pulling the UUV downward, via the recovery cable, through the upward-facing first end of the elongate recovery container. 
 
     
     
       12. The method of  claim 10 , wherein adjusting the at least one ballast tank comprises moving water from an aft ballast tank to a forward ballast tank. 
     
     
       13. The method of  claim 10 , wherein a stop is positioned on the recovery cable, wherein the UUV comprises a convex forward face, and wherein the method further comprises:
 after guiding the UUV toward the recovery cable, causing the convex forward face of the UUV to make contact with the recovery cable, below the stop, such that the recovery cable is displaced and drawn along a side of the UUV, wherein the capture clip comprises:
 a loop releasably coupled to the side of the UUV, wherein the loop comprises a gap that is closed by a gate, and wherein the loop surrounds an opening that is larger than a diameter of the recovery cable and smaller than a diameter of the stop; and 
 a lead cable coupling the loop to the nose portion of the UUV; 
 
 wherein releasably securing the UUV to the recovery cable comprises passing the recovery cable through the gap of the loop and into the opening; and 
 releasing the loop from the side of the UUV such that the UUV is releasably secured to the recovery cable via the lead cable. 
 
     
     
       14. The method of  claim 13 , wherein the gate comprises a spring, and wherein passing the recovery cable through the gap of the loop comprises opening the gate via a force applied by the recovery cable to the gate from an outside of the loop, thereby compressing the spring. 
     
     
       15. The method of  claim 13 , wherein the capture clip further comprises a guide finger positioned adjacent to the loop, and wherein the method further comprises:
 before passing the recovery cable through the gap of the loop, extending the guide finger from the side of the UUV, wherein the guide finger is shaped such that the recovery cable is biased toward the gap when in contact with a forward edge of the guide finger. 
 
     
     
       16. The method of  claim 10 , wherein causing the elongate recovery container to retract the recovery cable comprises winding the recovery cable onto a winch positioned within the elongate recovery container. 
     
     
       17. The method of  claim 16 , wherein the winch comprises a force sensor, and wherein the method further comprises:
 detecting, via the force sensor, a tensile force on the recovery cable that is above a threshold tensile force, wherein causing the elongate recovery container to retract the recovery cable is based on the detected tensile force. 
 
     
     
       18. The method of  claim 10 , wherein causing the elongate recovery container to retract the recovery cable comprises:
 receiving, from the UUV, an indication that the UUV is a predetermined distance from the elongate recovery container; and 
 based on the received indication, causing the elongate recovery container to retract the recovery cable after a predetermined length of time has elapsed from receiving the indication. 
 
     
     
       19. The method of  claim 10 , wherein causing the elongate recovery container to retract the recovery cable comprises:
 receiving, from the UUV, an indication that the UUV is releasably secured to the recovery cable. 
 
     
     
       20. A non-transitory computer readable medium having stored thereon instructions that, when executed by a computing device, cause the computing device to perform functions comprising:
 locating, via a forward looking sonar system of an unmanned underwater vehicle (UUV), a recovery cable that extends underwater in a vertical orientation, wherein the recovery cable is coupled to an elongate recovery container that is positioned underwater in a vertical orientation; 
 guiding the UUV toward the recovery cable; 
 releasably securing the UUV to the recovery cable via a capture clip coupled to a nose portion of the UUV; 
 adjusting at least one ballast tank to trim the UUV to a vertical orientation; and 
 causing the elongate recovery container to retract the recovery cable.